Without the ability to have a static build of sys-block/thin-provisioning-tools, anyone who wants /usr on a seperate partition from / must either modify both fsck and lvm initscripts or write extra initscripts to get the system to boot without error with filesystems on thin volumes.
There has been an announcement (a Portage GLEP42 news item) informing you need initramfs on Linux for separate /usr I'm only stating that, instead of closing this bug, to point out if you want such support you should be providing patches and not hold your breath otherwise
should be all set now in the tree; thanks for the report! Commit message: Add support for USE=static http://sources.gentoo.org/sys-block/thin-provisioning-tools/thin-provisioning-tools-0.5.3.ebuild?rev=1.1
